Difference Between Free Radical and Ionic Polymerization

The key difference between free radical and ionic polymerization is that free radical polymerization occurs through radicals that contain an unpaired electron whereas ionic polymerization occurs via ionic species that has no unpaired electrons.

1. What is the difference between anionic cationic and free radical polymerization?
2. What do you mean by free radical polymerization?
3. What is ionic vinyl polymerization?
4. Which catalyst is used in free radical polymerization?
5. Why anionic polymerization is called living polymerization?
6. What is the result of polymerization?
7. How free radicals are formed?
8. Which radicals most stable?
9. What are types of polymerization?
10. Why is anionic polymerization so useful?
11. What is the difference between cationic and anionic polymerization?
12. What type of alkenes prefer under cationic polymerization?

What is the difference between anionic cationic and free radical polymerization?

Anionic polymerization reactions yield more regular polymers with less branching, more controlled tacticity and narrow molecular weight distribution. ... Free-radical polymerization is the most versatile type of chain-growth polymerization.

What do you mean by free radical polymerization?

Free-radical polymerization (FRP) is a method of polymerization, by which a polymer forms by the successive addition of free-radical building blocks. Free radicals can be formed by a number of different mechanisms, usually involving separate initiator molecules.

What is ionic vinyl polymerization?

Ionic polymerization is a chain-growth polymerization in which active centers are ions or ion pairs. It can be considered as an alternative to radical polymerization, and may refer to anionic polymerization or cationic polymerization. As with radical polymerization, reactions are initiated by a reactive compound.

Which catalyst is used in free radical polymerization?

Chain transfer reactions are especially prevalent in the high pressure radical polymerization of ethylene, which is the method used to make LDPE (low density polyethylene). The 1º-radical at the end of a growing chain is converted to a more stable 2º-radical by hydrogen atom transfer.

Why anionic polymerization is called living polymerization?

Thus, since the propagating chain end maintains its reactivity and is still “living,” the resulting polymer and the polymerization system are called as “living polymer” and “living polymerization,” respectively.

What is the result of polymerization?

Polymerization, any process in which relatively small molecules, called monomers, combine chemically to produce a very large chainlike or network molecule, called a polymer. The monomer molecules may be all alike, or they may represent two, three, or more different compounds.

How free radicals are formed?

A molecule with one or more unpaired electron in its outer shell is called a free radical (1-5). Free radicals are formed from molecules via the breakage of a chemical bond such that each fragment keeps one electron, by cleavage of a radical to give another radical and, also via redox reactions (1, 2).

Which radicals most stable?

Allyl and benzyl free radicals are exceptionally stable as they are stabilized by resonance. We know that more the number of resonating structures, greater is the stability.

What are types of polymerization?

There are two basic types of polymerization, chain-reaction (or addition) and step-reaction (or condensation) polymerization. One of the most common types of polymer reactions is chain-reaction (addition) polymerization. This type of polymerization is a three step process involving two chemical entities.

Why is anionic polymerization so useful?

That delocalisation is always a powerful factor that allows ions to form more easily. In fact, we can easily choose an anionic initiator that is more reactive than that delocalised one, so that there is a driving force toward polymer initiation. Alkyllithiums, such as butyllithium, are good candidates.

What is the difference between cationic and anionic polymerization?

Cationic polymerization reactions are sensitive to temperature. Both the reaction rate and molecular weight rapidly decrease with increasing temperature. Anionic polymerization reactions typically yield more regular polymers with less branching, more controlled tacticity and narrow molecular weight (MW) distribution.

What type of alkenes prefer under cationic polymerization?

q Cationic polymerization of simple alkenes is especially efficient for alkenes which form relatively stable carbocations (note the tertiary carbocation intermediate) and which have one double bond terminus of the alkene unsubstituted, so as to minimize steric effects in the TS for the addition reaction.